1. Field of the Invention
The present invention relates to an electronic still camera and an electronic still camera system, in particular, to ones that provide, in accordance with a storing rate of a storage medium, a storable continuous frame count and a continuous shooting rate of frames at a time when an actual continuous frame count exceeds the storable continuous frame count.
2. Description of the Related Art
At continuous shooting by use of a conventional electronic still camera, image data of a shot object is temporarily stored in an internal memory and then is stored in a storage medium that is composed of semiconductor memories such as a compact flash memory, to finish the continuous shooting.
In this case, although the camera has a predetermined internal processing rate, the storing rate of the storage medium differs according to manufacturers or products so that the continuous shooting performance of the electronic still camera depends on the storing rate of a storage medium that the electronic still camera uses. When a storage medium whose storing rate is lower than the internal processing rate of the electronic still camera, the storable continuous frame count is limited by the storing rate of the storage medium.
Meanwhile, there has been a high request from users to know accurate continuous shooting performance of the electronic still camera. In response to their request, the conventional electronic still memory determines the upper limit of the storable continuous frame count in the continuous shooting mode in accordance with the capacity of internal memories. Alternatively, it lowers the continuous shooting rate of frames instead of determining the upper limit of the storable continuous frame count when frames are continuously shot beyond the capacity of the internal memory.
Japanese Unexamined Patent Application Publication No. 2001-169227 discloses a technique for reading the storing rate of a storage medium to display a residual shooting time in data recording apparatus that stores moving images and so forth.
With the above-described technique, the users can know in advance the storable continuous frame count in the continuous shooting mode if the upper limit of the storable continuous frame count is determined in accordance with the capacity of the internal memory. In recent years, however, there are storage media that have a plurality of internal buffers and has a storing rate higher than an internal processing rate of an electronic still camera. If such a storage medium is used with an electronic camera, it is not possible to increase the storable continuous frame count because of the lower storing rate of the camera. As a result, the user cannot fully take advantage of the features of the storage medium, and on that point conventional cameras have to be modified.
On the other hand, it is possible to increase the storable continuous frame count by use of the storage medium with a higher storing rate, if the upper limit of the storable continuous frame count is not set. However, in this case, the user cannot know of how many continuous frames are stored; therefore, the storage medium cannot meet the users' needs sufficiently. Besides, the user may not obtain desired images if he or she uses a storage medium with a lower storing rate because the user cannot know the continuous shooting rate of frames of when an actual continuous frame count exceeds the storable continuous frame count.
Furthermore, according to the technique disclosed in the above-mentioned Publication No. 2001-169227,the user cannot obtain accurate information on residual storage time and so forth at initial shooting or setting changes of the electronic still camera because the information is obtained according to the storing rate at which previous moving images were shot. Also, the technique has been developed on the precondition that the storing rate of the storage medium is to be equal to or lower than the internal processing rate of the electronic still camera. Moreover, it cannot solve the problems unique to the electronic still camera such as a decrease of the continuous shooting rate of frames of when an actual continuous frame count exceeds the storable continuous frame count.